Method for placing payload in orbit by multifunctional launch vehicle of combined scheme with cruise liquid rocket engine system (LRES), multifunctional launch vehicle of combined scheme with cruise LRES and method for refining it

ABSTRACT

The invention relates to the field of rocket-space engineering and may find application during the development of rocket-space systems serving to place manned and unmanned space ships into a near-earth orbit.  
     The method includes forming a launch assembly of a launch vehicle in accordance with a launch program, including a lower multiunit assembly of rocket units (RU), firing cruise LRESs of a central and side RUs at the launch, and operating the LRESs in accordance with the launch program. Identical RUs with adjustable LRESs of identical thrust are used to form the lower multiunit assembly. At the launch of the launch vehicle, LRESs of the side RUs have a nominal thrust, while the LRES of the central RU—a thrust equal to 90-100% of the nominal value. When the launch vehicle reaches a longitudinal acceleration of 12.7-16.7 m/sec 2 , the thrust of the LRES of the central RU is reduced to 0.3-0.5 of the nominal thrust until the LRESs of the side RUs are cut off. The reduction of the thrust of the LRESs of the side RUs is also presumed in order to adjust the inertial and aerodynamic loads on the launch vehicle.  
     The launch vehicle of a combined scheme comprises a lower multiunit assembly of RUs, composed of identical RUs, wherein the side RUs are mounted on the central RU symmetrically relative to its longitudinal axis in sectors formed by the swinging planes of the LRES of the central RU.  
     The method of refining the multifunctional launch vehicle presumes that during the selection of the characteristics of its RUs, identical size-mass characteristics and thrust of the LRESs of the lower multiunit assembly of RUs will be set, this ensuring use of the central RU in the makeup of a launch vehicle of a tandem scheme. The aforesaid RU is produced and its ground-based and flight-structural tests carried out, including in the makeup of a launch vehicle of a tandem scheme, and then it is used in the formation of a lower multiunit assembly of RUs of a launch vehicle of a combined scheme.  
     The main technical result from use of the invention is expansion of the range in which the payload being placed into orbit may change.

FIELD OF THE INVENTION

[0001] The invention relates to the field of rocket-space engineeringand may find application during the development of rocket-space systemsserving to place manned and unmanned spacecraft, and also other objectsof different purpose, on a near-earth orbit.

BACKGROUND OF THE INVENTION

[0002] The modern development of space engineering requires the creationof launch vehicles which are capable of delivering spacecraft ofdifferent purpose and mass to near-earth orbits at a height of 180-34000km. Where there is such a variety of tasks, the demand arises for thepresence of multifunctional launch vehicles which are capable in thebasic or other arrangement of performing these tasks. Launch vehicles ofa combined scheme with a multiunit lower stage satisfy this requirementin the best manner. Appropriately selecting the rocket units of thelower stage, it is possible over wide ranges to change thecharacteristics of the launch vehicle as a whole, achieving theirgreatest correspondence to the launch program. The advantages of launchvehicles of the combined scheme are manifested to the greatest degreewhen one of the rocket units of the lower multiunit stage, mainly thecentral, works for a longer period than the other units. Launch vehiclesof the combined scheme make it possible to also optimize the ascent ofspacecraft into a near-earth orbit.

[0003] A typical example of the use of a multiunit lower stage forplacing a payload into a near-earth orbit is the “Ariane” project, inparticular, “Ariane-5” (see, for example, Aviation Week and SpaceTechnology, No. 13, 1999, pp. 61, 64-65). The launch vehicle “Ariane-5”has a lower multiunit assembly of rocket units, including a centralrocket unit with a cruise LRES and two side rocket units with cruisesolid propellant rocket engines (SPREs). The project provides for theuse of two variants of a central rocket unit and several variants ofside rocket units with different operating times and thrust level of thecruise engines. An acceleration rocket unit and the head unit with thepayload are connected to the central rocket unit in accordance with atandem scheme. At lift-off both SPREs and the LRES of the central rocketunit are fired. When operation of the SPREs ceases, the side rocketunits are jettisoned and the launch vehicle continues acceleration withthe aid of the cruise LRES of the central rocket unit. When the launchvehicle “Ariane-5” with an enlarged central rocket unit is used, itpossible to place a payload with a mass of from 8 tons to 12 tons into anear-earth orbit from the KURU cosmodrome. In order to ascend a smallerpayload, for example, with a mass of 6 tons, another central unit withanother cruise LRES is necessary. Thus, when a typical construction of alaunch vehicle of a combined scheme is used, it is possible, withoutchanging the central rocket unit, to change the mass of the payloadbeing placed into orbit by 1.5 times, which is a typical range of changeof the mass of the payload for a modern launch vehicle of the combinedscheme. During the refinement of this launch vehicle, separaterefinement of the central rocket unit and the side rocket units in alltheir variants is necessary, and also the testing of differentassemblies of the launch vehicle. Since different variants of the rocketunits are used in the assembly of the launch vehicle, the refinement ofthe launch vehicle as a whole takes a large amount of time and requireslarge expenditures. Furthermore, operation of the launch vehicle ispossible only after refinement of at least one assembly of the centraland two side rocket units. A substantial drawback of all launch vehiclesof a combined scheme, which use side rocket units with SPREs, is theincreased ecological contamination of the atmosphere with compounds ofchlorine, which are contained in large amounts in the products ofcombustion of the solid propellant. The increase in the energeticcharacteristics of the solid propellant results in additionalcontamination of the atmosphere with toxic products of the combustion ofthe solid propellant.

[0004] Other variants of use of a combined launch vehicle for the ascentof a payload into a near-earth orbit are also proposed.

[0005] A method for placing a payload into orbit by a multifunctionallaunch vehicle of a combined scheme is known and disclosed in U.S. Pat.No. 4,964,340, class 102/377, B 64 G 1/40, Oct. 23, 1990. In accordancewith this patent an acceleration rocket unit and a head unit with apayload are mounted on a central rocket unit with a SPRE. A lowermultiunit assembly of rocket units is formed by connection of from twoto six side rocket units with SPREs to the central rocket unit inaccordance with a launch program. During lift-off of a launch vehiclewith six side rocket units, SPREs of four lift-off side rocket units arefired and acceleration of the launch vehicle begins. Prior to cuttingoff the aforesaid rocket units, SPREs of the two remaining side rocketunits are fired, after which the four spent rocket units are jettisonedand acceleration of the launch vehicle is continued with use of twoSPREs. Before they are cut off, the SPRE of the central rocket unit isfired and the two spent side rocket units are jettisoned. The rocketengines of the acceleration unit are fired after operation of the SPREof the central rocket unit has ended. The aforesaid method is realizedin a launch vehicle of a combined scheme, containing a lower multiunitassembly of rocket units with cruise SPREs, including a central andconnected thereto side rocket units and tandem secured on the centralunit transition compartment, acceleration rocket units and a head unitwith the payload, head domes of the side rocket units and a system forsecuring the side rocket units to the central unit. Two side rocketunits are connected to the central rocket unit in a pitch plane, forminga minimum assembly of a combined launch vehicle with three rocket unitsin the lower multiunit assembly. Two other variants of the launchvehicle, which realize this method, are formed by additionallyconnecting to the central rocket unit of the launch vehicle a minimumassembly of either two side rocket units, positioned in the pitch plane,or four side rocket units, positioned symmetrically relative to thepitch plane. The known technical solution makes it possible to use asingle-type SPRE for all the rocket units in the lower multiunitassembly, which significantly reduces the expenditures on placing thepayload into orbit. However, in this solution the energeticpossibilities of the lower multiunit assembly of rocket units is notused to the full extent, since during the first stage of operation ofthe launch vehicle a portion of the rocket units—three out of seven(more than 40%) for the variant with six side rocket units, does notparticipate in the process of creating thrust and is a passive massduring the first stage of placing the payload into orbit, which impairsthe engine weight efficiency of the launch vehicle and results in areduction of the mass of the payload to be placed in the near-earthorbit. During the realization of this method for placing a payload intoa near-earth orbit, higher loads will act on the launch vehicle as awhole and accordingly on the payload when the SPREs of the side rocketunits fire, they beginning to operate, for example, prior to terminationof operation of the SPREs of lift-off rocket units, since at the momentof firing the additional SPREs a thrust acts on the launch vehicle bothfrom lift-off SPREs and the thrust of the SPREs of two more side rocketunits. In spite of the fact that a single-type SPRE is used in therocket units, in this construction of the launch vehicle it is notpossible to use a standardized rocket unit, since in the case ofdifferent assemblies of the launch vehicle a central rocket unit isrequired with different positioning of the units for securing the siderocket units. During the refinement of this launch vehicle, in additionto refinement of the firing of rocket units with SPREs under on-groundconditions, refinement is necessary for firing these units underdifferent altitude conditions, as is presumed by the order of firingSPREs of the rocket units during the placement of the payload into theorbit with different assemblies of the launch vehicle. This launchvehicle is also not safe from the point of view of ecology, since ituses SPREs, the drawbacks of which were noted above.

[0006] A method for placing a payload into orbit by a launch vehicle ofa combined scheme is also known and disclosed in British patent No.1114414, class B7W2, FIGS. 4-8, May 22, 1968. In accordance with thispatent, an acceleration rocket unit with a payload, which unit isselected in accordance with the launch program, is mounted on the lowerstage. The multiunit assembly of rocket units of the lower stage isformed by connection of single-type, delta-like in plan, modules withcruise LRESs to each other with the formation of a pyramidal assembly.The number of modules in the pyramidal assembly may change from four tosix depending on the launch program. During lift-off of the launchvehicle the cruise LRESs of all the modules forming the pyramid arefired. The cruise LRESs of all the modules operate with an identicalthrust and are cut off simultaneously when the propellant in all themodules of the lower multiunit stage is consumed. All the modules of thelower multiunit stage are jettisoned simultaneously prior to firing thecruise LRES of the acceleration unit. The described method is realizedin a launch vehicle of a combined scheme, comprising a lower multiunitassembly of rocket units with cruise LRESs and tandem connected theretoacceleration unit. The lower multiunit stage is formed from single-type,delta-like in plan, modules, which have a triangular cross section.Modules with a spread angle of triangular cross section, correspondingto the number of assembly modules being joined, are used in each of thepyramidal assemblies. The modules are connected to each other alongadjacent surfaces. The known technical solution makes it possible to usea single-type LRES for all the rocket units of the lower multiunitassembly, which significantly reduces the expenditures on the placementof the payload into orbit. In spite of the use of a single-type LRES inthe rocket units of the lower multiunit assembly, in this constructionof the launch vehicle it is not possible to use a standardized rocketunit, since a module rocket unit with a different angle of spread oftriangular cross section is required for different assemblies of thelaunch vehicle. During the placement of the payload into orbit with theuse of the method described in this patent with the simultaneous cutoffof all the cruise LRESs of the lower multiunit assembly of rocket units,the main advantage of a combined launch vehicle—the possibility for morelengthy operation of the central unit, disappears, bringing the combinedlaunch vehicle to the traditional tandem arrangement with a heavierlower stage. During the refinement of this launch vehicle, therefinement of each modification of the module rocket unit included inthe lower multiunit assembly of rocket units is necessary, whichsignificantly increases the expenditures on the development of thelaunch vehicle and the cost of placing the payload into a near-earthorbit.

[0007] A method of placing a payload into orbit by a launch vehicle ofcombined scheme is also known and disclosed in U.S. Pat. No. 5,141,181,class 244/172, Aug. 25, 1992. In accordance with this patent when apayload is being placed into orbit by a multifunctional combined-schemelaunch vehicle with cruise LRESs in accordance with a launch program,tandem positioned rocket unit and head unit with the payload areconnected to the central rocket unit and a lower multiunit assembly ofrocket units is formed by connecting two or three side rocket units tothe central rocket unit. At lift-off the cruise LRESs of the side andcentral rocket units are fired and they are brought to the nominalthrust mode. In a non-emergency situation the cruise LRESs of the sideand central rocket units work together in the nominal thrust mode untilthe side rocket units are separated from the central, wherein the LRESof the central rocket unit works on a propellant supplied from tanks ofthe side rocket units. When the propellant from the side rocket units isconsumed, the latter units are jettisoned, and the LRES of the centralrocket unit continues to operate, using the propellant of the centralrocket unit. The launch vehicle contains a lower multiunit assembly ofrocket units with multiengine cruise LRESs, the assembly including acentral and connected thereto side rocket units, and an accelerationrocket unit and a head unit with the payload tandem secured on thecentral rocket unit. The launch vehicle is provided with a system forpumping propellant between the side rocket units and the central rocketunit. It is presumed that the construction of the launch vehicledescribed in the patent and the method for placing the payload into anear-earth orbit ensures guaranteed placement of the payload into theorbit when a multiengine cruise LRES is used, even if there is failureof one of the engines or the whole LRES of the central or one of theside rocket units, as a result of rational use of reserves of thepropellant of the central rocket unit and the side rocket units in thecruise LRES engines which have retained their working capacity. In thisinvention, an increased time of operation of the cruise LRES of thecentral rocket unit is provided as a result of its operation during thefirst stage on propellant fed from the side rocket units, which resultsin a reduction of the reliability of placing the payload into orbit,since there is a high probability that a defect in the propellantpumping system will appear, especially in the detachable connections ofthe pipelines between the rocket units. Another drawback of thisinvention is that it is impossible to standardize the side units and thecentral unit, since it is necessary to provide them with a differentnumber of pumping devices, which makes the refinement of the launchvehicle more complex, since the units for each assembly need to berefined separately.

[0008] The method most similar to the claimed method in respect to thecombination of material features is the method for placing a payloadinto orbit by a multifunctional launch vehicle of a combined scheme withcruise LRESs, which has been realized in the Soviet Union with use ofthe launch vehicle “Vostok,” which is used to place manned and unmannedspace ships with a mass Lip to 5 tons in a near-earth orbit (see, forexample, Launch Vehicles, V. A. Aleksandrov, V. V. Vladimirov, R. D.Dmitriev, S. O. Osipov, Senior Editor Prof. S. O. Osipov, Moscow,Voenizdat, 1981, pp. 19-22, FIG. 1.2). The known method includesconnecting tandem positioned acceleration rocket units and a head unitwith a payload to a central rocket unit in accordance with the launchprogram and forming a lower multiunit assembly of rocket units byconnecting side rocket units to the central rocket unit, firing atlift-off all the cruise LRESs of the side rocket units and the centralrocket unit, jointly operating the cruise LRESs of the central rocketunit and the side rocket units until the propellant of the side rocketunits is consumed, cutting off the cruise LRESs of the side rocket unitsand separating the side rocket units from the central rocket unit whilecontinuing operation of the cruise LRES of the central rocket unit untilthe propellant therein is consumed, cutting off the cruise LRES of thecentral rocket unit, separating the tandem positioned accelerationrocket unit and the head unit from the central rocket unit andsubsequently accelerating the head unit until its placement into orbit.

[0009] The launch vehicle “Vostok” itself comprises a lower multiunitassembly of rocket units with cruise LRESs, which work on kerosene andliquid oxygen and have a significantly less effect on ecology ascompared with the SPREs used in the “Ariane-5” project. The lowermultiunit assembly of rocket units includes a central and connectedthereto four side rocket units. A transition compartment, anacceleration rocket unit and a head unit with a payload are secured intandem on the central unit. The launch vehicle is provided with a systemfor securing the side rocket units to the central unit. The side rocketunits are provided with head domes. The central rocket unit has a largesize and large mass as compared with the side rocket units and carriesmore propellant in its tanks, which ensures more lengthy operation ofits cruise LRES. The cruise LRES of the central rocket unit has animmovably secured four-chamber main rocket engine and four steeringrocket engines. The LRES of each side rocket unit has an immovablysecured four-chamber main rocket engine and two steering rocket engines.Thus, the lower multiunit assembly of rocket units of the launch vehicle“Vostok” is assembled of nonidentical rocket units. The refinement ofthe launch vehicle “Vostok” included selection of the size-masscharacteristics of the central rocket unit, side and acceleration rocketunits and thrust characteristics of their cruise LRESs, designing andmanufacturing the aforesaid rocket units, forming therefrom the lowermultiunit assembly of rocket units, ground-based and flight-structuraltests to confirm the reliability of both separate rocket units and thelaunch vehicle as a whole. As in respect to the launch vehicle“Ariane-5,” during the refinement of the launch vehicle “Vostok,”separate refinement of the central rocket unit and the side rocket unitsis necessary with subsequent testing in assembly, which occupies a lotof time and requires large expenditures. Furthermore, operation of thelaunch vehicle “Vostok” is possible only after refinement of thearrangement of the central rocket unit and the side rocket units.

[0010] It is clear from the foregoing that the necessity exists forimprovement of the method for placing a payload into orbit and anexpendable launch vehicle with a changeable assembly, which would ensurethe delivery into different near-earth orbits of devices of differentmass and purpose with the simultaneous reduction of the cost of placingthe payload and the reduction of the time necessary to develop a launchvehicle.

[0011] The object to the achievement of which the claimed invention isdirected is to create a method for placing a payload into orbit by amultifunctional launch vehicle of a combined scheme with cruise LRESsand the launch vehicle itself, which ensure an expanded range of changeof the mass of the payload being placed into orbit with a minimum numberof varieties (types) of rocket units which are included in the assemblyof the launch vehicle. Another object to the achievement of which theclaimed invention is directed is to create a method for placing apayload into orbit by a multifunctional launch vehicle of a combinedscheme with cruise LRESs and the launch vehicle itself, ensuring aminimum change of the coordinates of descent of the spent side rocketunits when devices of different mass and purpose are placed into anear-earth orbit and accordingly a reduction of the dimensions of theclosed zone for the field of fall of spent rocket units.

[0012] An additional object of the invention is to create a method forplacing a payload into orbit by a multifunctional launch vehicle of acombined scheme with cruise LRESs, which ensures reduction of bothinertial and aerodynamic loads on the launch vehicle during flight.

[0013] Another object of the invention is to create a launch vehicle ofcombined scheme with cruise LRESs, which ensures a reduction of theexpenditures on its development and on its production as a result of theuse of a mini mum number of versions (types) of rocket units included inthe assembly of the launch vehicle and the increase of their massproduction.

[0014] One more object of the invention is to create a launch vehicle ofa combined scheme with cruise LRESs and a method for its refinement,which provide a reduction of the expenditures on the development of thelaunch vehicle and the possibility of starting its operation in alighter version at the earliest stages of development.

DISCLOSURE OF THE INVENTION

[0015] The technical objects indicated above are achieved in that in theknown method for placing a payload into orbit by a multifunctionallaunch vehicle of a combined scheme with cruise liquid rocket enginesystems (LRESs), including connecting tandem positioned accelerationrocket units and a head unit with a payload to a central rocket unit inaccordance with the launch program and forming a lower multiunitassembly of rocket units by connecting side rocket units to the centralrocket unit, firing all the cruise LRESs of the side rocket units andthe central rocket unit at lift-off, jointly operating the cruise LRESsof the central rocket unit and the side rocket units until thepropellant of the side rocket units is consumed, cutting off the cruiseLRESs of the side rocket units and separating the side rocket units fromthe central rocket unit while continuing operation of the cruise LRES ofthe central rocket unit until the propellant therein is consumed,cutting off the cruise LRES of the central rocket unit, separating thetandem positioned rocket units and head unit from the central rocketunit and subsequently accelerating the head unit by the aforesaid rocketunits until its placement into orbit, in accordance with the invention,identical rocket units having adjustable cruise LRESs with an identicalnominal thrust are used to form the lower multiunit assembly of rocketunits, at lift-off the launch vehicle is made to ascend by cruise LRESsof the side rocket units at a nominal thrust, and the cruise LRES of thecentral rocket unit—at a thrust equal to 90-100% of the nominal value,and it is kept constant until the launch vehicle reaches a longitudinalacceleration of 12.7-16.7 m/sec² (1.3-1.7 g), then the thrust of thecruise LRES of the central rocket unit is reduced to 0.3-0.5 of thenominal thrust, and after the cruise LRESs of the side rocket units arecut off, the thrust of the cruise LRES of the central unit is increasedto the nominal value.

[0016] Furthermore, during operation of the launch vehicle with a lowerlevel of the thrust of the cruise LRES of the central rocket unit, whenit reaches the longitudinal acceleration of 39-44 m/sec² (4-4.5 g), thethrust of the cruise LRESs of the side rocket units is smoothly reduced,maintaining the aforesaid longitudinal acceleration until termination ofoperation of the LRESs of the side rocket units.

[0017] Furthermore, during the atmosphere portion of the path, thealtitude of the flight of the launch vehicle and its velocity aremeasured, on the basis of which the dynamic pressure of the oncoming airflow at the density of a standard atmosphere at flight altitude isdetermined, and when the launch vehicle reaches the velocity at whichthe aerodynamic forces from the dynamic pressure of the oncoming airflow reach the values which are maximum permissible for the constructionof the launch vehicle, further increase of the velocity of the launchvehicle is carried out by adjustment of the thrust of the cruise LRESsof the side rocket units within the limits of 0.3-1.0 of the nominalthrust under condition that the maximum permissible dynamic pressure isnot exceeded, maintaining the relationship: $\begin{matrix}{V_{i} = {k\quad V_{i}\sqrt{\frac{\rho_{1}}{\rho_{i}}}}} & (1)\end{matrix}$

[0018] wherein:

[0019] V_(i) is the current velocity of the launch vehicle;

[0020] k is a dynamic coefficient equal to 0.95-1.05;

[0021] V₁ is the velocity of the launch vehicle at which the maximumpermissible dynamic pressure is reached;

[0022] ρ₁ is the density of standard atmosphere, at which the maximumpermissible dynamic pressure is reached;

[0023] ρ_(i) is the current density of standard atmosphere at the flightaltitude.

[0024] Wherein, the adjustment of the thrust of the cruise LRESs of theside rocket units is carried out under the condition that the maximumpermissible dynamic pressure, equal to 12000-17000 Pa, is not exceeded.

[0025] As applied to a multifunctional launch vehicle of a combinedscheme with cruise LRESs, the stated object is achieved in a launchvehicle comprising a lower multiunit assembly of rocket units withcruise LRESs, including a central and connected thereto side rocketunits and tandem secured on the central unit a transition compartment,acceleration rocket units and a head unit with a payload, head domes ofside rocket units, and a system for securing the side rocket units tothe central unit, in that in accordance with the invention, the lowermultiunit assembly is composed of identical rocket units havingidentical propellant tanks and identical cruise LRESs with adjustablethrust, secured in a gimbal suspension, the side rocket units aremounted on the central rocket unit symmetrically relative to itslongitudinal axis in sectors formed by swinging planes of the cruiseLRES of the central rocket unit so that the swinging planes of thecruise LRES of each side rocket unit are parallel to correspondingswinging planes of the cruise LRES of the central rocket unit.

[0026] The launch vehicle may be provided with two side rocket units,which are mounted on the central rocket unit in one plane that isoriented at an angle of 45° to one of the swinging planes of the cruiseLRES of the central rocket unit, or with four side rocket units mountedon the central rocket unit in two mutually perpendicular planes,oriented at an angle of 45° to the swinging planes of the cruise LRES ofthe central rocket unit.

[0027] As applied to a method of refining a multifunctional launchvehicle of a combined scheme with cruise LRESs, the stated object isachieved in that in a method for optimizing, including selecting thesize-mass characteristics of the central, side and acceleration rocketunits and the thrust characteristics of their cruise LRESs, designingand manufacturing the aforesaid rocket units, forming therefrom a lowermultiunit assembly of rocket units, conducting ground-based andflight-structural tests to confirm the reliability of both separaterocket units and the launch vehicle as a whole, in accordance with theinvention, identical size-mass characteristics and thrust of the cruiseLRESs are set for the central rocket unit and the side rocket units,this ensuring use of the central rocket unit in the makeup of a launchvehicle of a tandem scheme with a monounit lower stage, the aforesaidrocket unit is produced and ground-based and flight structural teststhereof are carried out, including in the makeup of the launch vehicleof the tandem scheme, reliability of the central rocket unit isconfirmed and the central rocket unit refined on a launch vehicle of atandem scheme is used when forming the lower multiunit assembly ofrocket units of the launch vehicle of a combined scheme with theconduction of flight-structural tests with an increased time ofoperation of the cruise LRES of the central rocket unit relative to thecruise LRESs of the side rocket units.

[0028] The essence of the invention is that forming in the launchvehicle of a combined scheme the lower multiunit assembly of identicalrocket units having identical fuel tanks and identical cruise LRESs, itis possible to expand the range of changing the mass of the payloadplaced in a near-earth orbit by simply increasing the side rocket unitsconnected to the central rocket unit. Wherein, as compared with knownrealized schemes for placement of a payload by combined launch vehicles,in the claimed method it is possible to significantly reduce theexpenditures on placing the payload into orbit as a result of usingmonotype standardized constructions. Using adjustable cruise LRESs inthe aforesaid rocket units makes it possible at lift-off to fullyrealize the energetic possibilities of the lower multiunit assembly ofrocket units, and subsequent reduction of the thrust of a cruise LRES ofthe central rocket unit to 0.3-0.5 of the nominal thrust guarantees thatthere is a reserve of propellant in the central rocket unit for itscruise LRES after separation of the side rocket units. A decrease of thethrust of the cruise LRES of the central rocket unit begins after alongitudinal acceleration of 12.7-16.7 m/sec² (1.3-1.7 g) has beenreached by the launch vehicle, this acceleration ensuring a stableposition of the launch vehicle in its path. An increase of the thrust ofthe cruise LRES of the central rocket unit to the nominal value afterthe cruise LRESs of the side rocket units are cut off makes it possibleto fully use the energetic possibilities of the central rocket unit.

[0029] A smooth reduction of the thrust of the cruise LRESs of the siderocket units when the launch vehicle reaches a longitudinal accelerationof 39-44 m/sec² (4-4.5 g) with the maintenance of this longitudinalacceleration until termination of operation of the side rocket unitsensures expansion of the range of the mass of the payload placed intoorbit, since it provides the possibility of avoiding redundant overloadswhen a payload with reduced mass is being placed into orbit. Wherein, itis also possible to achieve a minimum change of the coordinates of thefall of spent side rocket units and accordingly—reduction of the closedzone.

[0030] The proposed method makes it possible to limit the action on thelaunch vehicle of aerodynamic forces from the dynamic pressure of theoncoming air flow. In order to do this, when the maximum permissibledynamic pressure on the construction of the launch vehicle is reached, afurther increase of the velocity is carried out by adjusting the thrustof the cruise LRESs of the side rocket units within the range of 0.3-1.0of the nominal thrust under the condition that the maximum permissibledynamic pressure is not exceeded maintaining the indicated relationship(I).

[0031] A dynamic pressure of the oncoming air flow, which does notexceed 12000-17000 Pa, is the optimum dynamic pressure for theconstruction of a launch vehicle of combined scheme.

[0032] Securing the cruise LRESs of the central rocket unit and the siderocket units in a gimbal suspension and mounting the side rocket unitson the central rocket unit symmetrically relative to its longitudinalaxis in sectors which are formed by swinging planes of the cruise LRESof the central rocket unit, so that the swinging planes of the cruiseLRES of each side rocket unit are parallel to corresponding swingingplanes of the cruise LRES of the central rocket unit, ensures anidentical positioning of each side rocket unit and its cruise LRESrelative to the central rocket unit and its cruise LRES independent ofthe number of side rocket units included in the launch vehicle assembly,which makes it possible to use identical rocket units in the makeup ofthe launch vehicle with a standardized system for control of each siderocket unit.

[0033] When two or four side rocket units are secured on the centralrocket unit with their arrangement in planes oriented at an angle of 45°to the swinging planes of the cruise LRES of the central rocket unit,identicalness of the conditions of their operation is ensuredindependent of the number of side rocket units in the lower multiunitassembly.

[0034] The proposed method for placing a payload in orbit by amultifunctional launch vehicle of a combined scheme with cruise LRESsand the construction of the launch vehicle provide the possibility ofreducing the cost of development of the launch vehicle and to begin itsoperation at the very earliest stages of development, since in theproposed method of refinement, during the selection of the size-masscharacteristics of the central, side and acceleration rocket units andthe thrust characteristics of their cruise LRESs, identical size-masscharacteristics and thrust of the cruise LRESs are prescribed for thecentral and side rocket units. This provides the possibility of usingthe central rocket unit in the makeup of a launch vehicle of a tandemscheme with a monounit lower stage, which makes it possible after thecentral rocket unit has been manufactured and ground-based andflight-structural tests have been carried out to begin to use it withinthe makeup of a launch vehicle of a tandem scheme. After ascertainingthe reliability of the central rocket unit in this manner, the lowermultiunit assembly of rocket units of the launch vehicle of a combinedscheme is formed and flight-construction tests are carried out with agreater time of operation of the cruise LRES of the central rocket unitrelative to the cruise LRESs of the side rocket units.

[0035] The technical result from use of the proposed invention is theexpansion of the range of change of the mass of the payload being placedin a near-earth orbit, in particular, the launch vehicle of a combinedscheme being developed within the “Angara” project provides thepossibility of rocketing a payload of from 14 tons to 28.5 tons. The useof the central rocket unit, being developed in the “Angara” project, asa lower stage of a launch vehicle of a tandem scheme with placement of apayload with a mass of from 2 tons to 3.7 tons into a near-earth orbitis also possible.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036]FIG. 1 shows the general view of the proposed launch vehicle,heavy class;

[0037]FIG. 2 shows view A in FIG. 1;

[0038]FIG. 3 shows the section B-B in FIG. 2;

[0039]FIG. 4 shows the section C-C in FIG. 3;

[0040]FIG. 5 shows the general view of the proposed launch vehicle,middle class;

[0041]FIG. 6 shows view D in FIG. 5;

[0042]FIG. 7 shows a scheme for placing a payload into orbit;

[0043]FIG. 8 shows a graph of change of the thrust of a cruise LRES ofthe central rocket unit;

[0044]FIG. 9 shows a graph of a change of the thrust of a cruise LRES ofa side rocket unit with control of an inertial load;

[0045]FIG. 10 shows a graph of a change of the thrust of a cruise LRESof a side rocket unit with control of an aerodynamic load;

[0046]FIG. 11 shows a launch vehicle of a tandem scheme, in which acentral rocket unit is used as the first stage.

BEST METHOD OF CARRYING OUT THE INVENTION

[0047] A heavy-class launch vehicle comprises a lower multiunit assembly1 of rocket units, including a central rocket unit 2 and connectedthereto four side rocket units 3. The lower multiunit assembly iscomposed of identical rocket units, which have identical propellanttanks 4 and 5. The propellant tank 4 of each rocket unit 2 and 3 has avolume of 46 m³ and holds up to 36.5 tons of hydrocarbon fuel. Thepropellant tank 5 of each rocket unit 2 and 3 has a volume of 90 m³ andholds up to 96 tons of liquid oxygen. The central rocket unit 2 isprovided with an adjustable cruise LRES 6 with a nominal thrust of 196tons (1920 kN) and a minimum thrust of 58 tons. The side rocket units 3are provided with adjustable cruise LRESs 7. The cruise LRESs 7 arecompletely identical to the LRES 6 of the central rocket unit 2 andtheir thrust may also be adjusted within the range of from 58 tons to196 tons. The central and side rocket units are provided with reactivesystems for roll control (not shown in the drawing). The cruise LRES 6of the central rocket unit is secured in a gimbal suspension 8 with twomutually perpendicular swiveling axes, making it possible for the LRES 6to swing in two planes I-I and II-II. The swinging planes divide thecentral unit 2 into four vertical sectors. The side rocket units 3 aremounted on the central rocket unit 2 symmetrically relative to itslongitudinal axis in the aforesaid vertical sectors in two mutuallyperpendicular planes III-III and IV-IV, oriented at an angle of 45° tothe swinging planes of the cruise LRES 6 of the central rocket unit.

[0048] The cruise LRESs 7 of the side rocket units are secured in gimbalsuspensions 9 with two mutually perpendicular swiveling axes, making itpossible for the LRESs 7 to swing in two planes, similar to the cruiseLRES 6 of the central rocket unit. The swinging planes of the cruiseLRESs 7 of the side rocket units are parallel to corresponding swingingplanes of the cruise LRES 6 of the central rocket unit. The gimbalsuspensions 8 and 9 are shown in FIG. 4 schematically, since theirconstruction is not the subject of the invention according to theinstant application and may use constructions of LRES gimbalsuspensions, which are known in rocket engineering.

[0049] The system for securing the side rocket units includes hingepower joints for fixing the side rocket units relative to the centralrocket unit, which joints are positioned in lower 10 and upper 11girders. The construction of the fixation units is not givenconsideration in the instant application. The side rocket units areprovided with head domes 12. A transition compartment 13, anacceleration rocket unit 14 and a head unit 15, in which the payloadwith a mass of 24.5-28.5 tons to be placed into near-earth orbit isarranged, are secured in tandem on the central rocket unit.

[0050] The proposed invention makes it possible, using a standardizedcentral rocket unit, to assemble a middle class launch vehicle of acombined scheme as shown in FIGS. 5 and 6. The middle class launchvehicle comprises a lower multiunit assembly 1 of rocket units, theassembly including a central rocket unit 2 and connected thereto twoside rocket units 3. The central and side rocket units of this rocket inrespect to construction and dimensions are completely identical to therocket units of the heavy class launch vehicle and use the sameadjustable cruise LRESs with the thrust changed from 58 tons to 196tons. The side rocket units 3 are mounted on the central rocket unitsymmetrically relative to its longitudinal axis and are positioned inone plane oriented at an angle of 45° to the swinging plane of thecruise LRES of the central rocket unit.

[0051] As an example of realization of the method, consideration will begiven to the placement of a payload with a mass of 26-28 tons into anear-earth orbit with the aid of a heavy-class launch vehicle. Thesequence of the steps of placing the payload with the aid of a launchvehicle of combined scheme, shown in FIG. 7, includes:

[0052] launching the launch vehicle with simultaneous operation of thecruise LRESs of the central and the side rocket units (position E);

[0053] separating exhausted side rocket units from the central rocketunit (position F);

[0054] accelerating the launch vehicle with the aid of the cruise LRESof the central rocket unit (position G). At this step, the dome of thehead unit is cast off;

[0055] firing the cruise LRES of the acceleration unit and separating itfrom the central rocket unit (position H);

[0056] moving the payload into orbit with the aid of the LRES of thehead unit (position J).

[0057] In accordance with the launch program the lower multiunitassembly 1 of rocket units is formed, connecting four side rocket units3 to the central rocket unit 2. An acceleration rocket unit 14 with acruise LRES having a thrust of 30 tons (294 kN) and a head unit 15 withthe payload are also connected to the central rocket unit.

[0058] At the lift-off, the cruise LRESs 6 and 7 of the central and siderocket units are fired and each of them is brought to the nominal thrustof 196 tons, obtaining a sum thrust at lift-off of 980 tons.Acceleration is begun with the launch vehicle in a vertical positionuntil a stable position of the launch vehicle is reached on the path,after which a turn in the vertical plane begins. When a longitudinalacceleration of 14.7 m/sec² (1.5 g) is reached, the thrust of the cruiseLRES 6 of the central rocket unit begins to decrease and it is reducedto 58 tons (570 kN). Further acceleration of the launch vehicle iscarried out at a constant thrust of 58 tons of the cruise LRES 6 of thecentral rocket unit right up to burnout of the propellant from the tanksof the side rocket units and cut-off of their cruise LRESs 7. Thisprovides the possibility at the moment of cutting off the cruise LRESs 7of the side rocket units to retain in the tanks of the central rocketunit up to 18 tons of hydrocarbon fuel and up to 49 tons of liquidoxygen, which is sufficient to deliver the payload into a near-earthorbit. After the cruise LRESs 7 of the side rocket units are cut off,the thrust of the cruise LRES 6 of the central rocket unit is increasedto the nominal value of 196 tons, while the exhausted side rocket unitsare separated from the central rocket unit and acceleration of thelaunch vehicle is continued during operation of the LRES of the centralrocket unit at the nominal thrust right up to burnout of the propellantfrom the tanks of the central rocket unit. A typical graph of change ofthe thrust R_(t) of the cruise LRES of the central rocket unit is shownin FIG. 8 in which a change of the longitudinal acceleration N_(x) ofthe launch vehicle is also shown. After cutoff of the cruise LRES 6 ofthe central rocket unit, the latter is cast off, the LRES of theacceleration rocket unit 14 is fired and further placement of thepayload into orbit is carried out by the cruise LRES of the accelerationunit and, where necessary, by the rocket engine itself of the head unit15.

[0059] During the placement of a payload with a mass of 23-24 tons intoa near-earth orbit by a heavy-class launch vehicle, the necessity arisesto control the cruise LRESs of the side rocket units in order to reducethe inertial loads on both the construction of the launch vehicle and onthe payload. In order to solve this problem during the operation of alaunch vehicle with a thrust level of the cruise LRES of the centralrocket unit equal to 58 tons, when it reaches its longitudinalacceleration of 39-44 m/sec² (4-4.5 g), the thrust of the cruise LRESs 7of the side rocket units is uniformly reduced, maintaining the aforesaidlongitudinal acceleration until the end of operation of the LRESs of theside rocket units. The cruise LRESs 7 of the side rocket units make itpossible to adjust the thrust within the range of 30-100% of the nominalvalue of a similar cruise LRES 6 of the central rocket unit. A typicalgraph of change of the thrust R_(t) of the cruise LRESs 7 of the siderocket units when the maximum permissible value of the longitudinalacceleration N_(x) is reached is shown in FIG. 9.

[0060] Adjustment of the thrust of cruise LRESs of the central and siderocket units also provides the possibility to ensure selection of thearea of fall of exhaust side and central rocket units, since it makes itpossible, controlling the thrust of the cruise LRESs of these units towiden the variation of kinematic parameters of the launch vehicle at themoments of separating the side and central rocket units.

[0061] The necessity for adjustment of the aerodynamic loads acting onthe construction of the launch vehicle may arise in the atmosphereportion of the path. In order to do this the altitude of the flight ofthe launch vehicle and its velocity are measured, in accordance withwhich the dynamic pressure Q_(t) of the oncoming air flow at the densityof a standard atmosphere at the flight altitude is determined. When thelaunch vehicle reaches a velocity at which the aerodynamic forces fromthe dynamic pressure of the oncoming air flow reach the maximumpermissible values for the construction of the launch vehicle, furtherincrease of the velocity of the launch vehicle is accomplished byadjustment of the thrust of the cruise LRESs of the side rocket unitswithin the range of 0.3-1.0 of the nominal thrust under condition thatthe maximum permissible dynamic pressure is not exceeded, maintainingthe relationship (1). In the case of the launch vehicle being givenconsideration as an example, the maximum permissible dynamic pressureshould not exceed 13000-15000 Pa. A typical graph of change of thethrust R_(t) of the cruise LRESs 7 of the side rocket units whenadjustment of the aerodynamic load acting on the construction of thelaunch vehicle is made is shown in FIG. 10. The change of the dynamicpressure of the oncoming air flow in the absence of adjustment of thevelocity of the launch vehicle is shown by the dashed line in FIG. 10. Alimitation of the dynamic pressure of the oncoming air flow acting onthe construction of the launch vehicle provides the possibility ofincreasing the mass of the payload being placed into near-earth orbit.

[0062] Refinement of the launch vehicle is accomplished in the followingmanner. The size-mass characteristics of the central, side andacceleration rocket units and the thrust characteristics of their cruiseLRESs are selected, wherein identical size-mass characteristics andthrust of the cruise LRESs, ensuring the use of the central rocket unitin the makeup of the tandem scheme launch vehicle with a monounit lowerstage, are defined for the central and the side rocket units. In thevariant of a combined launch vehicle of heavy and middle class underconsideration, the following parameters were taken for the centralrocket unit:

[0063] thrust of the cruise LRES-196 tons;

[0064] diameter-2.9 m;

[0065] length (from the upper bottom of the oxidizer tank to the nozzleexit section)-25 m;

[0066] takeoff mass with filled oxidizer and fuel tanks-142 tons.

[0067] These parameters make it possible to use the central rocket unitin a launch vehicle of a tandem scheme as its lower stage to place apayload with a mass of from 2 tons to 3.7 tons into a near-earth orbit.

[0068] Similar characteristics were set for the side rocket units. Thecharacteristics of the acceleration and head units were set on the basisof the mass of the payload.

[0069] The aforesaid rocket units are designed and produced and theirground-based and flight-structural tests are carried out. The centralrocket unit is tested in the makeup of a launch vehicle of a tandemscheme and its use begins in a launch vehicle of a light-class tandemscheme to place payloads of from 2 tons to 3.7 tons into a near-earthorbit (FIG. 11). This makes it possible to rapidly obtain statistic datain order to confirm the reliability of a produced rocket unit and toreduce expenditures on the refinement of a combined launch vehicle,since both experimental and operating launches of the rocket unit willbe taken into account in the statistics. The rocket unit which has beenrefined on a launch vehicle of a tandem scheme is used during theformation of the lower multiunit of an assembly of rocket units of alaunch vehicle of a combined scheme, variants of which are shown in FIG.1 and FIG. 5. Flight-structural tests are carried out with an increasedtime of operation of the cruise LRES of the central rocket unit ascompared with the cruise LRESs of the side rocket units, this confirmingthe reliability of the launch vehicle of the combined scheme.

1. A method for placing a payload into orbit by a multifunctional launchvehicle of a combined scheme with cruise liquid rocket engine systems(LRESs), including connecting tandem positioned acceleration rocketunits and a head unit with a payload to a central rocket unit inaccordance with a launch program and forming a lower multiunit assemblyof rocket units by connecting side rocket units to the central rocketunit, firing all the cruise LRESs of the side rocket units and thecentral rocket unit at lift-off, jointly operating the cruise LRESs ofthe central rocket unit and the side rocket units until the propellantof the side rocket units is consumed, cutting off the cruise LRESs ofthe side rocket units and separating the side rocket units from thecentral rocket unit while continuing operation of the cruise LRES of thecentral rocket unit until the propellant therein is consumed, cuttingoff the cruise LRES of the central rocket unit, separating the tandempositioned rocket units and head unit from the central rocket unit andsubsequently accelerating the head unit by said rocket units until itsplacement into orbit, characterized in that identical rocket unitshaving adjustable cruise LRESs with an identical nominal thrust are usedto form the lower multiunit assembly of rocket units, at lift-off thelaunch vehicle is made to ascend by cruise LRESs of the side rocketunits at a nominal thrust, and the cruise LRES of the central rocketunit—at a thrust equal to 90-100% of the nominal value, and the thrustof the LRES of the central rocket unit is kept constant until the launchvehicle reaches a longitudinal acceleration of 12.7-16.7 m/sec² (1.3-1.7g), then the thrust of the LRES of the central rocket unit is reduced to0.3-0.5 of the nominal thrust, and after the cruise LRESs of the siderocket units are cut off, the thrust of the cruise LRES of the centralunit is increased to the nominal value.
 2. A method according to claim1, characterized in that during operation of the launch vehicle with alower level of the thrust of the cruise LRES of the central rocket unit,when it reaches the longitudinal acceleration of 39-44 m/sec² (4-4.5 g),the thrust of the cruise LRESs of the side rocket units is smoothlyreduced, maintaining said longitudinal acceleration until termination ofoperation of the LRESs of the side rocket units.
 3. A method accordingto claim 1, characterized in that during the atmosphere portion of thepath, the altitude of the flight of the launch vehicle and its velocityare measured, on the basis of which the dynamic pressure of the oncomingair flow at the density of a standard atmosphere at flight altitude isdetermined, and when the launch vehicle reaches the velocity at whichthe aerodynamic forces from the dynamic pressure of the oncoming airflow reach the values which are maximum permissible for the constructionof the launch vehicle, further increase of the velocity of the launchvehicle is carried out by adjustment of the thrust of the cruise LRESsof the side rocket units within the limits of 0.3-1.0 of the nominalthrust under condition that the maximum permissible dynamic pressure isnot exceeded, maintaining the relationship: $\begin{matrix}{V_{i} = {k\quad V_{i}\sqrt{\frac{\rho_{1}}{\rho_{i}}}}} & (1)\end{matrix}$

wherein: V_(i) is the current velocity of the launch vehicle; k is adynamic coefficient equal to 0.95-1.05; V₁ is the velocity of the launchvehicle at which the maximum permissible dynamic pressure is reached; ρ₁is the density of standard atmosphere, at which the maximum permissibledynamic pressure is reached; ρ_(i) is the current density of standardatmosphere at the flight altitude.
 4. A method according to claim 3,characterized in that the adjustment of the thrust of the cruise LRESsof the side rocket units is carried out under the condition that themaximum permissible dynamic pressure, equal to 12000-17000 Pa, is notexceeded.
 5. A multifunctional launch vehicle of a combined scheme withcruise LRESs, the launch vehicle comprising a lower multiunit assemblyof rocket units with cruise LRESs, including a central and connectedthereto side rocket units and tandem secured on the central unit atransition compartment, acceleration rocket units and a head unit with apayload, head domes of side rocket units, and a system for securing theside rocket units to the central unit, characterized in that the lowermultiunit assembly is composed of identical rocket units havingidentical propellant tanks and identical cruise LRESs with adjustablethrust, secured in a gimbal suspension, the side rocket units aremounted on the central rocket unit symmetrically relative to itslongitudinal axis in sectors formed by swinging planes of the cruiseLRES of the central rocket unit so that the swinging planes of thecruise LRES of each side rocket unit are parallel to correspondingswinging planes of the cruise LRES of the central rocket unit.
 6. Alaunch vehicle according to claim 5, characterized in that it isprovided with two side rocket units, which are mounted on the centralrocket unit in one plane that is oriented at an angle of 45° to one ofthe swinging planes of the cruise LRES of the central rocket unit.
 7. Alaunch vehicle according to claim 5, characterized in that it isprovided with four side rocket units mounted on the central rocket unitin two mutually perpendicular planes, oriented at an angle of 45° to theswinging planes of the cruise LRES of the central rocket unit.
 8. Amethod of refining a multifunctional launch vehicle of a combined schemewith cruise LRESs, including selecting the size-mass characteristics ofcentral, side and acceleration rocket units and thrust characteristicsof their cruise LRESs, designing and manufacturing said rocket units,forming therefrom a lower multiunit assembly of rocket units, conductingground-based and flight-structural tests to confirm the reliability ofboth separate rocket units and the launch vehicle as a whole,characterized in that identical size-mass characteristics and thrust ofthe cruise LRESs are set for the central rocket unit and the side rocketunits, this ensuring use of the central rocket unit in the makeup of alaunch vehicle of a tandem scheme with a monounit lower stage, saidrocket unit is produced and ground-based and flight-structural teststhereof are carried out, including in the makeup of the launch vehicleof the tandem scheme, reliability of the central rocket unit isconfirmed and the central rocket unit refined on a launch vehicle of atandem scheme is used when forming the lower multiunit assembly ofrocket units of the launch vehicle of a combined scheme with theconduction of flight-structural tests with an increased time ofoperation of the cruise LRES of the central rocket unit relative to thecruise LRESs of the side rocket units.